The study of interval graphs was spearheaded by Benzer [1]} in his studies in the field of molecular biology. In [2]}, Zhang introduced a generalization of interval graphs called probe interval graphs (PIG) in an attempt to aid a problem called cosmid contig mapping. In order to obtain a better model another generalization of interval graphs were introduced that capture the property of overlap information, namely tagged probe interval graphs (TPIG) by Sheng, Wang and Zhang in [3]}. Still there is no recognition algorithm for TPIG, in general.
